This proposal describes a novel fiber optic sensor for the measurement of moisture at elevated temperatures. The sensor relies on films that contain flourescent compounds sensitive only to the presence of water molecules. By monitoring the changes in fluorescence with a fiber optic interface, it is possible to determine, in near real-time, the local moisture levels. The proposed sensor has two innovative features. It employs a single fiber configuration for both excitation and emission, and it uses a multiwavelength detection method which provides an internal standard for continuous calibration for better measurement accuracy. To advance this technique towards a commercially viable instrument, a work plan is proposed to design, construct and test a pre-prototype, fiber optic based flourescent moisture sensor. It consists of four main tasks: (1) preparation of films on fiber tips; (2) setting-up a single fiber optic configuration; (3) selection of light source and detection methods; and (4) testing and evaluation in environments characteristic of food processing operations such as microwave heating and baking. If Phase I is successful, it will lead to a low cost, rugged and fast response moisture sensor that is immune from electrical and magnetic fields, and that can efficiently carry out signal modulation, internal calibration and remote sampling. Applications to baking and drying operations are envisioned as well as to other areas where electrically and chemically immune moisture detection is needed.
Anticipated Results/Potential Commercial Applications of Research:: It is anticipated that this effort will lead to a unique, fiber optic sensor for moisture measurement far ahead of its competitors. The combination of rapid response, self-calibration, low cost, and remote monitoring will find vast commercial applications in the food and drug industries, as well as in chemicals and munitions manufacturing, where the need for rapid determination of humidity levels is very critical to process optimization and products performance.
